The present invention relates to a key switch for a computer keyboard, and more particularly to such a computer key switch, which enables the key cap to be smoothly stably moved up and down during operation.
A key switch for a computer keyboard is generally comprised of a rubber cone mounted on a membrane circuit above a frame, and a key cap having a bottom plunger inserted through an axle hole on a locating board and supported on the rubber cone. When the key cap is depressed, the plunger is lowered with the key cap to compress the rubber cone, causing the rubber cone to trigger a corresponding contact at the membrane circuit. This structure of key switch is still not satisfactory in function. If the applied force is not employed to the center area of the key cap, the key cap tends to be tilted, causing the plunger to be stuck in the axle hole on the locating board. Taiwan Patent Publication #370220 and #194192 disclose two structures of key switch for computer keyboard. In these two structures of key switch, an additional spring member and a spring cap are installed to support and guide movement of the key cap. These two structures of key switch are complicated and expensive to manufacture. Further, if the user depresses the corner area of the key cap, the applied force cannot be evenly distributed through the plunger of the key cap, thereby causing the key cap to be tilted during its movement, resulting in a triggering error.